High platelet distribution width suggests that platelet volume is not uniform in size and can be seen in diseases such as acute myeloid leukemia, megaloblastic anemia, and chronic granulocytic leukemia. Platelet distribution width is the width of distribution of platelet volume in blood, which is a parameter reflecting the discrete size of platelets. Platelet distribution width within the normal range suggests that platelets are uniform in size. High platelet distribution width refers to the platelet volume disparity, uneven size, can be seen in leukemia, such as acute myeloid leukemia, chronic granulocytic leukemia, but also can be seen in megaloblastic anemia, splenectomy, thrombotic diseases. Warm tips: when high platelet distribution width occurs, the cause should be identified in time, and treatment should be carried out under the guidance of doctors if necessary.